A pedestrian walks in the snow along Ski Run Boulevard in South Lake Tahoe, Calif., Tuesday, Nov. 10, 2015. The wet-weather system heading moving across California from the Pacific to the Sierra Nevada brought cool, wet weather to low-lying areas and snow to the mountains. (Caitlin Row/Tahoe Daily Tribune via AP) MANDATORY CREDIT

DENVER (AP) — A strong storm system dropping light snow on Denver was making travel hazardous as it headed east Wednesday morning, menacing the Plains with heavy snow and threatening turbulent weather — even tornadoes — in Iowa, Missouri.

Colorado troopers reported several crashes on windy, icy Interstate 25 near the Wyoming border, and flights have been canceled at Denver International Airport.

Airport spokesman Heath Montgomery said airlines canceled about 50 flights in anticipation of the bad weather — just a small portion of the airport’s 1,500 daily flights. He said ground crews have been able to keep up with the snow. The FAA was slowing morning flights into Denver to spread out traffic and avoid longer delays.

National Weather Service meteorologist Todd Dankers said up to 12 inches have been reported in the Rockies and around 3 inches fell on Denver. The Denver total could hit 4 inches by the time the system leaves the area.

Forecaster Jared Guyer with the weather service’s Storm Prediction Center in Norman, Oklahoma, said the back side of the fast-moving system will run into more cold air over Kansas and Nebraska, leaving behind up to 8 inches in some spots.

A winter storm warning or blizzard warning was in effect for parts of Utah, New Mexico, Wyoming, Colorado, Nebraska and Kansas through Wednesday afternoon and evening in some places. Sustained winds of 30 to 40 mph were expected, with gust up to 55 or even 60 mph.

The weather service cited the potential for white-out conditions and urged people to stay home.

A day earlier, up to 18 inches of wet, heavy snow fell in Nevada, shuttering schools in Reno and knocking out power to thousands.

At Pi Kappa Cino Coffee in Sterling, Colorado, workers on Tuesday were checking their heaters and stocking up on coffee to handle the first significant snowfall of the season.